Chemistry and Stability - Sodium hypochlorite is an alkaline inorganic chemical compound with the chemical formula NaOCl. - Its molar mass is 74.442 g/mol. - It appears as a greenish-yellow solid in its pentahydrate form. - Sodium hypochlorite is highly unstable in its anhydrous form and decomposes explosively. - The decomposition is accelerated by carbon dioxide. - It can be obtained as a stable crystalline pentahydrate and is stable when refrigerated. - Sodium hypochlorite solutions can lose strength over time.

Equilibria and Decomposition - Sodium hypochlorite is more stable in dilute solutions containing solvated Na and OCl ions. - The density of the solution varies with concentration. - Solutions are fairly stable at pH 11-12. - Sodium hypochlorite can disproportionate to chloride and chlorate under certain conditions. - This reaction occurs at high temperatures, forming sodium chlorate and sodium chloride. - An alternative decomposition of hypochlorite produces oxygen instead of chlorate. - The decomposition reactions are maximised at pH around 6.

Production Methods - Reaction of sodium carbonate with chlorinated lime is a common method used in the past. - Electrolysis of brine is another method that involves the electrolysis of brine to produce sodium hydroxide and chlorine gas, which are then mixed to form sodium hypochlorite. - Production of solid stable dihydrate NaOCl·2H2O involves reacting chloride-free solution of hypochlorous acid with sodium hydroxide and removing sodium chloride by filtration. - Concentrated slurries of the pentahydrate NaClO·5H2O can be produced using a similar principle. - Sodium hypochlorite is packaged and sold under various trade names.

Uses and Applications - Sodium hypochlorite is commonly used as a disinfectant and bleach. - It is used in water treatment to kill bacteria and viruses. - It can be used for stain removal and deodorizing. - Sodium hypochlorite is used in the production of paper and textiles. - It is also used in the pharmaceutical and food industries.

Environmental Impact and Safety - Sodium hypochlorite has limited environmental impact as the hypochlorite ion degrades rapidly before being absorbed by living beings. - Concerns arise from the formation of persistent chlorinated organic compounds, including known carcinogens, which can enter the food chain. - Sodium hypochlorite should be handled with care as it can cause skin and eye irritation. - It should not be mixed with other chemicals, especially acids, as it can release toxic gases. - Proper ventilation and personal protective equipment should be used when handling sodium hypochlorite.